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https://www.readbyqxmd.com/read/29785667/cerebral-autoregulation-in-stroke
#1
REVIEW
Pedro Castro, Elsa Azevedo, Farzaneh Sorond
PURPOSE OF REVIEW: Cerebral autoregulation (CA) is a mechanism that maintains cerebral blood flow constant despite fluctuations in systemic arterial blood pressure. This review will focus on recent studies that measured CA non-invasively in acute cerebrovascular events, a feature unique to the transcranial Doppler ultrasound. We will summarize the rationale for CA assessment in acute cerebrovascular disorders and specifically evaluate the existing data on the value of CA measures in relation to clinical severity, guiding management decisions, and prognostication...
May 21, 2018: Current Atherosclerosis Reports
https://www.readbyqxmd.com/read/29767351/evaluating-the-methods-used-for-measuring-cerebral-blood-flow-at-rest-and-during-exercise-in-humans
#2
REVIEW
Michael M Tymko, Philip N Ainslie, Kurt J Smith
The first accounts of measuring cerebral blood flow (CBF) in humans were made by Angelo Mosso in ~1880, who recorded brain pulsations in patients with skull defects. In 1890, Charles Roy and Charles Sherrington determined in animals that brain pulsations-assessed via a similar method used by Mosso-were altered during a variety of stimuli including sensory nerve stimulation, asphyxia, and pharmacological interventions. Between 1880 and 1944, measurements for CBF were typically relied on skull abnormalities in humans...
May 16, 2018: European Journal of Applied Physiology
https://www.readbyqxmd.com/read/29766604/sodium-nitroglycerin-induces-middle-cerebral-artery-vasodilation-in-young-healthy-adults
#3
Jenna M Schulz, Baraa K Al-Khazraji, J Kevin Shoemaker
Recent evidence indicates that basal cerebral conduit vessels dilate with hypercapnia, with a nitric oxide (NO) mechanism explaining one way in which parenchymal cerebral arterioles dilate. However, whether NO affects basal cerebral artery dilation remains unknown. This study quantified the effect of an exogenous NO donor [sodium nitroglycerin (NTG); 0.4 mg sublingual spray] on the right middle cerebral artery (rMCA) cross-sectional area (CSA), blood velocity and overall blood flow. Measures of vessel CSA (7 Tesla magnetic resonance imaging) and MCA blood velocity (transcranial Doppler ultrasound) were made at baseline (BL), and following exogenous NTG or placebo (PLO) administration in young, healthy individuals (n = 10, 2 males, age range 20-23 years)...
May 15, 2018: Experimental Physiology
https://www.readbyqxmd.com/read/29761991/-study-of-neuronal-spike-frequency-adaptation-with-transcranial-magneto-acoustical-stimulation
#4
Yi Yuan, Na Pang, Yudong Chen, Hongbao Sun, Xiaoli Li
Transcranial magneto-acoustical stimulation (TMAS), utilizing focused ultrasound and a magnetostatic field to generate an electric current in tissue fluid to regulate the activities of neurons, has high spatial resolution and penetration depth. The neuronal spike-frequency adaptation plays an important role in the treatment of neural information. In this paper, we study the effects of ultrasonic intensity, magnetostatic field intensity and ultrasonic frequency on the neuronal spike-frequency adaptation based on the Ermentrout neuron model...
December 1, 2017: Sheng Wu Yi Xue Gong Cheng Xue za Zhi, Journal of Biomedical Engineering, Shengwu Yixue Gongchengxue Zazhi
https://www.readbyqxmd.com/read/29758099/the-reduction-in-treatment-efficiency-at-high-acoustic-powers-during-mr-guided-transcranial-focused-ultrasound-thalamotomy-for-essential-tremor
#5
Alec Hughes, Yuexi Huang, Michael L Schwartz, Kullervo Hynynen
PURPOSE: To analyze clinical data indicating a reduction in the induced energy-temperature efficiency relationship during transcranial focused ultrasound (FUS) essential tremor (ET) thalamotomy treatments at higher acoustic powers, establish its relationship with the spatial distribution of the focal temperature elevation, and explore its cause. METHODS: A retrospective observational study of patients (N = 19) treated between July 2015-August 2016 for Essential Tremor (ET) by FUS thalamotomy was performed...
May 14, 2018: Medical Physics
https://www.readbyqxmd.com/read/29750475/effects-of-losartan-and-allopurinol-on-cardiorespiratory-regulation-in-obstructive-sleep-apnoea
#6
Barbara J Morgan, Mihaela Teodorescu, David F Pegelow, Emily R Jackson, Devin L Schneider, David T Plante, James P Gapinski, Scott J Hetzel, John M Dopp
Chemoreflex sensitization produced by chronic intermittent hypoxia (CIH) in rats is attenuated by angiotensin II type 1 receptor (AT1 R) blockade. AT1 R blockade and xanthine oxidase inhibition both ameliorate CIH-induced endothelial dysfunction. We hypothesized treatment with losartan and allopurinol would reduce chemoreflex sensitivity and improve hypoxic vasodilation in patients with obstructive sleep apnoea (OSA). Eighty-six hypertensive patients with apnoea-hypopnoea index ≥25 events/hr and no other cardiovascular, pulmonary, renal, or metabolic disease were randomly assigned to receive allopurinol, losartan, or placebo for 6 weeks...
May 11, 2018: Experimental Physiology
https://www.readbyqxmd.com/read/29744017/spontaneous-recanalization-after-carotid-artery-dissection-the-case-for-an-ultrasound-only-monitoring-strategy
#7
Sarah Lumsden, Gabor Rosta, Jean Bismuth, Alan B Lumsden, Zsolt Garami
Dissection of the internal carotid artery (ICA) accounts for 5% to 25% of ischemic strokes in young adults. We report a case of spontaneous recanalization of a traumatic ICA dissection in which carotid duplex (CDU) and transcranial color-coded duplex ultrasound (TCCD) were used. A 47-year-old male presented with intermittent episodes of headache, blurry vision, anisocoria, and loss of taste sensation following a whiplash injury while body surfing. Magnetic resonance angiogram (MRA) of the neck revealed absent flow in the cavernous ICA and a clot at the skull base...
October 2017: Methodist DeBakey Cardiovascular Journal
https://www.readbyqxmd.com/read/29734963/treatment-of-a-patient-with-task-specific-writing-tremor-using-magnetic-resonance-guided-focused-ultrasound
#8
Ying Meng, Suganth Suppiah, Nadia Scantlebury, Nir Lipsman, Michael L Schwartz
Task-specific dystonia is characterized by abnormal repetitive movements or postures in a specific body part that is triggered and ends with a task, such as writing. Failing medications, surgery, specifically disruption of key nuclei in the thalamus, can provide excellent symptomatic relief. Transcranial magnetic resonance (MR)-guided focused ultrasound is an emerging incision-less thermoablation technique. We describe MR-guided focused ultrasound tandem ablation of the ventral intermediate and ventralis oralis posterior nuclei in a 60-year-old patient with writer's cramp...
May 8, 2018: Canadian Journal of Neurological Sciences. le Journal Canadien des Sciences Neurologiques
https://www.readbyqxmd.com/read/29733278/design-and-characterization-of-an-acoustically-and-structurally-matched-3-d-printed-model-for-transcranial-ultrasound-imaging
#9
Chen Bai, Meiling Ji, Ayache Bouakaz, Yujin Zong, Mingxi Wan
For investigating human transcranial ultrasound imaging (TUI) through the temporal bone, an intact human skull is needed. Since it is complex and expensive to obtain one, it requires that experiments are performed without excision or abrasion of the skull. Besides, to mimic blood circulation for the vessel target, cellulose tubes generally fit the vessel simulation with straight linear features. These issues, which limit experimental studies, can be overcome by designing a 3-D-printed skull model with acoustic and dimensional properties that match a real skull and a vessel model with curve and bifurcation...
May 2018: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/29732592/transcranial-doppler-ultrasound-in-peninsular-arab-patients-with-sickle-cell-disease
#10
Adekunle Adekile, Meaad Hassan, Akram Asbeutah, Mohamed Al-Hinai, Omar Trad, Nayef Farhan
OBJECTIVES: Transcranial Doppler ultrasound is used to identify patients with sickle cell disease (SCD) at risk for stroke. We performed transcranial Doppler studies in patients from 4 countries in the Arabian Peninsula (Kuwait, Oman, Iraq, and United Arab Emirates) to document the prevalence of abnormal transcranial Doppler findings. METHODS: The patients were recruited from outpatient clinics and studied in a steady state. Transcranial Doppler examinations were performed with standard equipment by experienced operators...
May 6, 2018: Journal of Ultrasound in Medicine: Official Journal of the American Institute of Ultrasound in Medicine
https://www.readbyqxmd.com/read/29727515/microv-technology-to-improve-transcranial-color-coded-doppler-examinations
#11
Giovanni Malferrari, Giuseppe Pulito, Attilia Maria Pizzini, Nicola Carraro, Giorgio Meneghetti, Enzo Sanzaro, Patrizio Prati, Antonio Siniscalchi, Daniela Monaco
The purpose of this review is to provide an update on technology related to Transcranial Color Coded Doppler Examinations. Microvascularization (MicroV) is an emerging Power Doppler technology which can allow visualization of low and weak blood flows even at high depths, thus providing a suitable technique for transcranial ultrasound analysis. With MicroV, reconstruction of the vessel shape can be improved, without any overestimation. Furthermore, by analyzing the Doppler signal, MicroV allows a global image of the Circle of Willis...
May 4, 2018: Journal of Neuroimaging: Official Journal of the American Society of Neuroimaging
https://www.readbyqxmd.com/read/29722303/harnessing-migraines-for-neural-regeneration
#12
REVIEW
Jonathan M Borkum
The success of naturalistic or therapeutic neuroregeneration likely depends on an internal milieu that facilitates the survival, proliferation, migration, and differentiation of stem cells and their assimilation into neural networks. Migraine attacks are an integrated sequence of physiological processes that may protect the brain from oxidative stress by releasing growth factors, suppressing apoptosis, stimulating neurogenesis, encouraging mitochondrial biogenesis, reducing the production of oxidants, and upregulating antioxidant defenses...
April 2018: Neural Regeneration Research
https://www.readbyqxmd.com/read/29675962/dual-wavelength-hybrid-optoacoustic-ultrasound-biomicroscopy-for-functional-imaging-of-large-scale-cerebral-vascular-networks
#13
Johannes Rebling, Héctor Estrada, Sven Gottschalk, Gali Sela, Michael Zwack, Georg Wissmeyer, Vasilis Ntziachristos, Daniel Razansky
A critical link exists between pathological changes of cerebral vasculature and diseases affecting brain function. Microscopic techniques have played an indispensable role in the study of neurovascular anatomy and functions. Yet, investigations are often hindered by sub-optimal trade-offs between the spatiotemporal resolution, field-of-view and type of contrast offered by the existing optical microscopy techniques. We present a hybrid dual-wavelength optoacoustic biomicroscope capable of rapid transcranial visualization of large-scale cerebral vascular networks...
April 19, 2018: Journal of Biophotonics
https://www.readbyqxmd.com/read/29674994/a-cross-sectional-study-on-cerebral-hemodynamics-after-mild-traumatic-brain-injury-in-a-pediatric-population
#14
Corey M Thibeault, Samuel Thorpe, Michael J O'Brien, Nicolas Canac, Mina Ranjbaran, Ilyas Patanam, Artin Sarraf, James LeVangie, Fabien Scalzo, Seth J Wilk, Ramon Diaz-Arrastia, Robert B Hamilton
The microvasculature is prominently affected by traumatic brain injury (TBI), including mild TBI (concussion). Assessment of cerebral hemodynamics shows promise as biomarkers of TBI, and may help inform development of therapies aimed at promoting neurologic recovery. The objective of this study was to assess the evolution in cerebral hemodynamics observable with transcranial Doppler (TCD) ultrasound in subjects suffering from a concussion at different intervals during recovery. Pediatric subjects between the ages of 14 and 19 years clinically diagnosed with a concussion were observed at different points post-injury...
2018: Frontiers in Neurology
https://www.readbyqxmd.com/read/29670392/cerebral-blood-flow-velocity-in-migraine-and-chronic-tension-type-headache-patients
#15
S Karacay Ozkalayci, B Nazliel, H Z Batur Caglayan, C Irkec
Introduction: The present study seeks to use transcranial Doppler ultrasound to evaluate cerebral blood flow velocities in anterior and posterior circulation arteries, during an attack-free episode in migraine patients, with and without aura, as well as in chronic tension-type headache patients who were not receiving prophylactic medication. Methods: A total of 50 patients (35 female, 15 male) were evaluated during a headache-free episode: 30 migraine patients without aura (mean age: 32±8 years), 10 migraine patients with aura (mean age: 34±4 years), and 10 patients with chronic tension-type headache (mean age: 34±5 years)...
2018: Journal of Pain Research
https://www.readbyqxmd.com/read/29667598/a-random-phased-array-for-mr-guided-transcranial-ultrasound-neuromodulation-in-non-human-primates
#16
Vandiver Chaplin, Marshal A Phipps, Charles F Caskey
Transcranial focused ultrasound (FUS) is a non-invasive technique for therapy and study of brain neural activation. Here we report on the design and characterization of a new MR-guided FUS transducer for neuromodulation in non-human primates at 650 kHz. The array is randomized with 128 elements 6.6 mm in diameter, radius of curvature 7.2 cm, opening diameter 10.3 cm (focal ratio 0.7), and 46% coverage. Simulations were used to optimize transducer geometry with respect to focus size, grating lobes, and directivity...
April 18, 2018: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/29659999/increased-body-mass-index-associated-with-reduced-risk-of-delayed-cerebral-ischemia-and-subsequent-infarction-after-aneurysmal-subarachnoid-hemorrhage
#17
Lorenzo Rinaldo, Alejandro A Rabinstein, Giuseppe Lanzino
BACKGROUND: Increased body mass index (BMI) may be protective against cerebral ischemia in certain clinical contexts. OBJECTIVE: To investigate whether increased BMI was associated with delayed cerebral ischemia (DCI) and subsequent infarction after aneurysmal subarachnoid hemorrhage (aSAH). METHODS: We retrospectively reviewed the clinical course of patients presenting to our institution for management of aSAH. Patient were segregated according to BMI< or ≥29...
April 4, 2018: Neurosurgery
https://www.readbyqxmd.com/read/29658494/multi-resolution-simulation-of-focused-ultrasound-propagation-through-ovine-skull-from-a-single-element-transducer
#18
Kyungho Yoon, Wonhye Lee, Phillip Croce, Amanda Cammalleri, Seung-Schik Yoo
Transcranial focused ultrasound (tFUS) is emerging as a non-invasive brain stimulation modality. Complicated interactions between acoustic pressure waves and osseous tissue introduce many challenges in the accurate targeting of an acoustic focus through the cranium. Image-guidance accompanied by a numerical simulation is desired to predict the intracranial acoustic propagation through the skull; however, such simulations typically demand sophisticated computation, which warrants an expedited processing method to provide on-site feedback for the user in guiding the acoustic focus to a particular brain region...
April 16, 2018: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/29649509/cybersickness-related-changes-in-brain-hemodynamics-a-pilot-study-comparing-transcranial-doppler-and-near-infrared-spectroscopy-assessments-during-a-virtual-ride-on-a-roller-coaster
#19
Alireza Mazloumi Gavgani, Rachel H X Wong, Peter R C Howe, Deborah M Hodgson, Frederick R Walker, Eugene Nalivaiko
Our aim was to assess cerebral blood flow changes during cybersickness. Transcranial Doppler (TCD) ultrasound and near infrared spectroscopy (NIRS) were used separately in two independent experiments. In both studies, a 15-min virtual roller coaster ride was used as a provocative visual stimulus. Subjective nausea ratings were obtained at 1 min intervals. The TCD study was performed in 14 healthy subjects (8 males and 6 females); in this study we also measured heart rate and arterial pressure. In a separate study a 52-channel NIRS device (Hitachi ETG-4000) was used to monitor activated brain regions by measuring oxy-hemoglobin (HbO2) concentration in 9 healthy subjects (4 male, 5 females)...
April 9, 2018: Physiology & Behavior
https://www.readbyqxmd.com/read/29614647/reduced-cerebrovascular-reserve-capacity-as-a-biomarker-of-microangiopathy-in-alzheimer-s-disease-and-mild-cognitive-impairment
#20
Barbora Soukupova Urbanova, Jaroslava Paulasova Schwabova, Hana Magerova, Petr Jansky, Hana Markova, Martin Vyhnalek, Jan Laczo, Jakub Hort, Ales Tomek
BACKGROUND: Cerebral microangiopathy in Alzheimer's disease (AD) causes chronic hypoperfusion and probably accelerates neurodegenerative changes. OBJECTIVE: We hypothesize microvascular impairment could be present already in mild cognitive impairment (MCI) and can be revealed using transcranial color-coded sonography (TCCS) and the breath-holding maneuver. METHODS: Three groups of subjects (AD in the stage of dementia, MCI, and cognitively normal controls) with detailed neuropsychological testing and low cerebrovascular burden (no history of stroke, no intra- or extracranial artery stenoses, and no severe vascular lesions on brain MRI), underwent a TCCS assessment of peak systolic (PSV), mean flow (MFV), and end diastolic velocities (EDV) and resistance and pulsatility indices (RI, PI) in large intracranial vessels bilaterally...
March 24, 2018: Journal of Alzheimer's Disease: JAD
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